move random data generation out to category for easier use

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@37558 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,10 +1,17 @@
+2014-01-08  Richard Frith-Macdonald <rfm@gnu.org>
+
+	* Source/NSUUID.m:
+	* Source/Additions/NSData+GNUstepBase.m: 
+	* Headers/GNUstepBase/NSData+GNUstepBase.h: 
+	Move random data generation out to the NSData(GNUstepBase) category.
+
 2014-01-07  Quentin Mathe <quentin.mathe@gmail.com>
 
 	* Source/NSJSONSerialization.m (writeObject()): Fixed double number 
-	serialization to encode 17 significant digits (this matches the max number 
-	of significant digits in the double-precision floating point format). This 
-	prevents a loss of precision, in case the number has more than 3 digits 
-	after the decimal point.
+	serialization to encode 17 significant digits (this matches the max
+        number of significant digits in the double-precision floating point
+        format). This prevents a loss of precision, in case the number has
+        more than 3 digits after the decimal point.
 	* Tests/base/NSJSONSerialization/json.m: Updated to test double number  
 	serialization. 
 

Headers/GNUstepBase/NSData+GNUstepBase.h

@@ -37,6 +37,16 @@ extern "C" {
 #if	OS_API_VERSION(GS_API_NONE,GS_API_LATEST)
 
 @interface NSData (GNUstepBase)
+
+/** Returns an autoreleased data instance initialised with pseudo-random
+ * bytes of the specified length.<br />
+ * On failure returns nil.  This may be due to:<br />
+ * A zero length or unreasonably large length argument or,<br />
+ * Failure to allocate memory to hold the random data or,<br />
+ * Failure of the underlying random data generation.
+ */
++ (id) dataWithRandomBytesOfLength: (NSUInteger)length;
+
 /**
  * Returns an NSString object containing an ASCII hexadecimal representation
  * of the receiver.  This means that the returned object will contain

Source/Additions/NSData+GNUstepBase.m

@@ -31,11 +31,87 @@
 
 #include <ctype.h>
 
+#if	defined(__MINGW32__)
+#include <wincrypt.h>
+#else
+#include <fcntl.h>
+#endif
+
+static int
+randombytes(uint8_t *buf, unsigned len)
+{
+#if	defined(__MINGW32__)
+
+  HCRYPTPROV hProvider = 0;
+
+  if (!CryptAcquireContextW(&hProvider, 0, 0,
+    PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
+    {
+      return -1;
+    }
+
+  if (!CryptGenRandom(hProvider, len, buf))
+    {
+      CryptReleaseContext(hProvider, 0);
+      return -1;
+    }
+
+  CryptReleaseContext(hProvider, 0);
+
+#else
+
+  int		devUrandom;
+  ssize_t	bytesRead;
+
+  devUrandom = open("/dev/urandom", O_RDONLY);
+  if (devUrandom == -1)
+    {
+      return -1;
+    }
+  bytesRead = read(devUrandom, buf, len);
+  close(devUrandom);
+  if (bytesRead != len)
+    {
+      return -1;
+    }
+
+#endif
+  return 0;
+}
+
 /**
  * Extension methods for the NSData class.
  */
 @implementation NSData (GNUstepBase)
 
++ (id) dataWithRandomBytesOfLength: (NSUInteger)length
+{
+  uint8_t       *buf = 0;
+  NSData        *d;
+
+  if (0 == length || length > 0xffffffff)
+    {
+      return nil;       // Unreasonable length for random data
+    }
+  buf = malloc(length);
+  if (0 == buf)
+    {
+      return nil;       // Not enough memory for random data
+    }
+  if (randombytes(buf, (unsigned)length) < 0)
+    {
+      free(buf);
+      return nil;       // Unable to generate the random data
+    }
+  d = [[self alloc] initWithBytesNoCopy: buf length: length freeWhenDone: YES];
+  if (nil == d)
+    {
+      free(buf);
+      return nil;       // Unable to create NSData instance
+    }
+  return AUTORELEASE(d);
+}
+
 /**
  * Returns an NSString object containing an ASCII hexadecimal representation
  * of the receiver.  This means that the returned object will contain

Source/NSUUID.m

@@ -26,12 +26,8 @@
 #import "common.h"
 #import "Foundation/NSCoder.h"
 #import "Foundation/NSUUID.h"
+#import "GNUstepBase/NSData+GNUstepBase.h"
 
-#if	defined(__MINGW32__)
-#include <wincrypt.h>
-#else
-#include <fcntl.h>
-#endif
 
 static int uuid_from_string(const char *string, unsigned char *uuid);
 static void string_from_uuid(const unsigned char *uuid, char *string);
@@ -260,6 +256,7 @@ static void string_from_uuid(const unsigned char *uuid, char *string)
 
 static int random_uuid(unsigned char *uuid)
 {
+  NSData        *rnd;
   unsigned char timeByte;
   unsigned char sequenceByte;
 
@@ -268,40 +265,13 @@ static int random_uuid(unsigned char *uuid)
    * problems (and are more work...)
    */
 
-#if	defined(__MINGW32__)
-
-  HCRYPTPROV hProvider = 0;
-
-  if (!CryptAcquireContextW(&hProvider, 0, 0,
-    PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
+  rnd = [NSData dataWithRandomBytesOfLength: kUUIDByteCount];
+  if (nil == rnd)
     {
       return -1;
     }
 
-  if (!CryptGenRandom(hProvider, kUUIDByteCount, uuid))
-    {
-      CryptReleaseContext(hProvider, 0);
-      return -1;
-    }
-
-  CryptReleaseContext(hProvider, 0);
-#else
-
-  int		devUrandom;
-  ssize_t	bytesRead;
-
-  devUrandom = open("/dev/urandom", O_RDONLY);
-  if (devUrandom == -1)
-    {
-      return -1;
-    }
-  bytesRead = read(devUrandom, uuid, kUUIDByteCount);
-  close(devUrandom);
-  if (bytesRead != kUUIDByteCount)
-    {
-      return -1;
-    }
-#endif
+  memcpy(uuid, [rnd bytes], kUUIDByteCount);
 
   /* as required by the RFC, bits 48-51 should contain 0b0100 (4)
    * and bits 64-65 should contain 0b01 (1)